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Human Biology
Human Body
Three students made different statements about cells and the human body.
This is what they said:
Herman: “The human body is made up entirely of a collection of trillions
of cells and things made from cells.”
Felix:
“The human body is surrounded by an outer covering. Inside
this covering the body is filled in with cells and things made
from cells.”
Diandra: “The human body is a collection of trillions of cells and things
made from cells contained inside an outer covering and inner
coverings that contain organs.”
Which student do you think best describes the human body? _________________.
Explain your thinking.
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Uncovering Student Ideas in Life Science
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Human Biology
Human Body
Teacher Notes
Purpose
The purpose of this assessment probe is to
elicit students’ ideas about the cellular makeup
of the human body. The probe is designed to
see if students recognize that the body is an
organized collection of cells and not a structure or “outline” that contains or is filled in
with cells.
Related Concepts
Human body, cells
Explanation
The best answer is Herman’s: “The human
body is made up entirely of a collection of trillions of cells and things made from cells.” The
human body is a complex system of cells that
starts with a single, fertilized cell that divides
to form an adult human organism made up
of trillions of cells. Some students may think
the body contains cells, rather than being
cellular in composition (and containing cell
secretions).
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Students who select Diandra may draw on
experiences where they learned that blood cells
travel through the veins and arteries and that
these structures contain cells inside of them.
What they fail to realize is that veins and arteries are also made up of cells that form vascular
tissue. Some students have similar conceptions
of organs inside the human body. They may
think organs are “sacs” filled with cells that
perform a special function. Likewise, some
students do not recognize skin as being cellular. They may think skin covers the body and
that contained inside the skin are structures
made of cells. Students who select Felix may
have a conception of the body as a sac filled in
with cells and cellular material.
Curricular and Instructional
Considerations
Elementary Students
At the elementary level, younger students learn
about the parts of the body that are visible to
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Human Biology
them. In the intermediate grades, students learn
about internal structures, with an emphasis on
major body organs. Students may be introduced to the cells, sometimes with the phrase
“the human body contains cells,” which may
give rise to an early conception that the body is
like a “sac” filled with organs and cells, rather
than with the clearer phrase, “the human body
is made up of cells.”
Middle School Students
At the middle level, students learn about the
hierarchical arrangement of the human body,
including the idea that the cell is the basic unit
of both function and structure in the human
body. Although students understand that the
body is made up of cells, they may not understand that the body is cellular, rather than
filled with cells.
High School Students
In high school, students deepen their understanding of cells, including the structures that
make up cells and the molecules that make
up cell structures. However, they may still
conceptualize the human body as a structure
that contains cells rather than being made up
of cells.
Administering the Probe
This probe is best used with upper elementary
and middle school students. Make sure students know that the probe is asking what the
body is made of. It does not include things like
the food and waste products inside the body
that do not become a part of the structures that
make up the body. You may wish to clarify the
distinction between the three statements. The
first statement means the body is cellular—it
is composed entirely of cells or materials that
come from cells, such as fingernails. The second statement means the body has a covering
inside of which there are cells, as well as internal sacs, such as organs, that have cells inside
of them. The covering is not considered to be
entirely made up of cells or cell materials. The
third statement means that the body has a covering that is not considered to be entirely made
up of cells or cell materials, and that filling the
inside of the body are cells and materials that
are not made of cells.
Related Ideas in National
Science Education Standards
(NRC 1996)
5–8 Structure and Function in Living
Systems
All organisms are composed of cells—the
fundamental unit of life. Most organisms
are single cells; other organisms, including
humans, are multicellular.
9–12 The Cell
• Cells can differentiate, and complex multicellular organisms are formed as a highly
organized arrangement of differentiated
cells.
Related Ideas in Benchmarks
for Science Literacy
(AAAS 2009)
3–5 The Cell
• Microscopes make it possible to see that
living things are made mostly of cells.
6–8 The Cell
All living things are composed of cells,
from just one to many millions, whose
details usually are visible only through a
microscope.
• Different body tissues and organs are made
up of different kinds of cells.
Related Research
• Dreyfus and Jungwirth’s (1988) research
showed that even though students are
Indicates a strong match between the ideas elicited by the probe and a national standard’s learning goal.
Uncovering Student Ideas in Life Science
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Human Biology
introduced to the cell as the basic building block of life, many believe that cells are
inside the body or that the body “contains”
cells, rather than that the body is composed of cells.
Suggestions for Instruction and
Assessment
• This probe can be combined with “Human
Body Basics” from Uncovering Student
Ideas in Science, Vol. 1: 25 Formative Assessment Probes, which addresses the idea that
the cell is the basic unit of both structure
and function in the human body (Keeley,
Eberle, and Farrin 2005).
• Be aware that providing outlines of the
human body and having students draw
in the organs may contribute to students
assuming that the human body is a sac
filled with organs that contain cells.
• When students learn about parts of the
body such as tendons and ligaments, point
out that these structures are formed partly
of cells and of cell secretions such as collagen and fibrin. Ask students where hair
and fingernails come from. Point out
that structures like hair and fingernails,
although not composed of cells, arose from
and were made from cell proteins.
Related Curriculum Topic Study
Guides (in Keeley 2005)
“Cells”
“Human Body Systems”
References
American Association for the Advancement of Science (AAAS). 2009. Benchmarks for science literacy online. www.project2061.org/publications/
bsl/online
Dreyfus, A., and E. Jungwirth. 1988. The cell concept of 10th graders: Curricular expectations
and reality. International Journal of Science Education 10: 221–229.
Keeley, P. 2005. Science curriculum topic study:
Bridging the gap between standards and practice.
Thousand Oaks, CA: Corwin Press and Arlington, VA: NSTA Press.
Keeley, P., F. Eberle, and L. Farrin. 2005. Uncovering student ideas in science, vol. 1: 25 formative
assessment probes. Arlington, VA: NSTA Press.
National Research Council (NRC). 1996. National
science education standards. Washington, DC:
National Academies Press.
Related NSTA Science Store
Publications, NSTA Journal
Articles, NSTA SciGuides,
NSTA SciPacks, and NSTA
Science Objects
American Association for the Advancement of Science (AAAS). 2001. Atlas of science literacy. Vol.
1. (See “Cell and Organs” map, pp. 74–75.)
Washington, DC: AAAS.
Science Object: Cell Structure and Function: The
Basis of Life
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